My 97 lt1 is having problems. It has headers and gutted MAF. At about 3000 rpm there is what souds like an ehaust leak on the pass side. But way more serious than that. There is also a bad rattle that sounds like a heat shield on the pass side up front. Sounds like the converter is rattling inside. Car is also way down on power and then will pick up and then back to no power. Could the guts in the converter be broken loose and clogging it up causing too much backpressure? It just started doing this yesterday. The rattle has benn there for a while, but seems worse now. What do you think?

 

I had exactly the same problem and it was the cat converter broken up inside plugging the outlet of the converter. I knocked the pieces out of the converter and performance returned with a new exhaust note that I think sounds great.